Our long range goals are to understand the mechanisms of cell division and the changes which occur in these mechanisms when cells undergo neoplastic transformation. This study is based upon our observations that the duration of metaphase in transformed cells is longer than in normal cells and that the degree of prolongation may be related to the mode of transformation. Our aims are 1.) to determine the scope and generality of these findings, 2.) to determine the relationship between increase in metaphase duration and the increase in heteroploidy which occurs in transformed cells, 3.) to determine the relationship between increased metaphase durations and the increase in metaphase-to-prophase ratios observed in a number of tumors and 4.) to try to gain some insight into the control of mitotic events. Our methods will include quantitative analyses of time lapse cinemicrographic films of a variety of transformed and nontransformed cells in culture and an examination of the possibility of a correlation between metaphase duration and changes in karyotype of human and other mammalian cells. We will also attempt to gain a better understanding of the physiology of the metaphase stage and how it is altered in transformed cells by studying the response of such cells, as observed by time lapse cinemicrography, to agents which alter intracellular levels of calcium ions and cyclic AMP.